Telescopic hydraulic jack



N0V 18 1952 J. L. GRArzMuLLER 2*,618-,1'2'2 l 'rELEscoPIc HYDRAULIC .mex

Filed Aug. 25, 1947 4 sheds-sheet' 1 u lr/ 9.2

NGV 18, 1952 J. L. GRATZMULLER 2,618,122

TELEscoPxc HYDRAULIC JACK Filed Aug. 25, 1947 4 Sheets-Sheet 2 Je@ nLOUA s GFQ-mulle Nuvi 'TOR Nov. 18, 1952 J. L. GRATzMuLLER 2,618,122

TELEscoPIc HYDRAULIC JACK y Filedv Aug. 25, 1947 4 Shasta-sheet s JaarwLQU'IS Grqf' Thuile( 4 INVENTCME EM AT1-V5 Nov. 18, 1952 J. L.GRATzMuLLr-:n 2,618,122

TELESCOPIC HYDRAULIC JACK Filed Aug. 25, 1947 4 sheets-sheet 4 @MM/@ amPatented Nov. 18, 1952 TELESCQBIQ HYDRAULIC- JACK Jean LouisGratzmuller, Paris, France Application Augusty 25, 1947, Serial No.770,346 In France April 18, 1946 section. i, Public, Law 69o, August s,1941s` 'Patent expires April 18;,'1966 i Claims.

Many proposals have hitherto been made with a View to procuring reliablesealing, guiding and stroke limiting means forl telescoping parts ofhydraulic lifting jacks.

- However, the telescopic parts for such jacks, hitherto proposed, aregenerally too complicated and necessitate a particularly'accuratemachining of the various requisite members thereof.

- It is an objectv ofthe present invention to provide in a hydrauliclifting jack' reliable sealing, guiding and stroke limiting means forthe telescopiiigparts. which will be simple in yconstruction and inmounting, and which will do away with the--necessity-of laccuratemachining, while p ossessing the requisite qualities. l

The sealing, guiding and stroke limiting means designed according to thepresent invention include substantially an annular sealing and guidinggasket set suitably interposed between the end portions of each twoparts intended to be telescoped into each other, guiding memberscooperatingwith said gasket set for guiding the desired telescopicmovements of said parts, and abutment members adapted to support saidgasket set and .tolimit the said telescopic movements.

In the present form, said gasket set is const'tuted by a metalliccollarwhose entire lowermost portion is bottomed with an expansble membersupported by one of the said abutment means, said collar and expansiblemember being jammed in between the walls of corresponding telescopingparts, in a recess managed aty the end ofl one of saidl parts.

Said guidi-'ng means are constituted bythe me'-l talli'c portion of saidgasket set and by longitudinallysuperimposed suitable' annular members'suitably fixed between the walls of respective telescoping parts, someof these members being u-sed at the same time as dirt catchers.

Said abutment means may be constituted either by suitable annularshoulders managed on" the Walls of respective telescoping parts, orpreferably by packstrings of the class including piano strings housed insuitable annular grooves managed in the wallsv of respective telescopingparts.

The sealing, guiding and stroke limiting means as hereinabove outlinedaccording to the invention arev particularly applicable to hydraulic orpneumatic llifting jacks, more particularly to jacks of the telescopictype.

tis. therefore, a further object of thev present invention to providev alifting jack ofv this kind in which particularly advantageous use ismade of the above-outlined sealing, guiding and stroke limiting means.

Other objects of the present invention will 'be apparent from thefollowing detailed description and the accompanying drawings inwhich;

Fig. 1 is an axial sectional View showing a sealing and guiding gasketaccording to thefin'vention,

mounted on a piston displaceable in a cylinder;

Fig. 2 is an axial sectional View showing a hydraulic telescopic liftingjack provided with seal'- ng and guiding gasket according to the inven'-ion; Y

Fig. 3 is an axial sectional view showing stroke: limiting and abutmentmeans according to the invention;

Fig. 4 is an axial sectional viewv showing a modi-- ed form of hydraulictelescoping lifting jack provided with sealing, guiding and strokelimiting means according to the invention;-

Fig. 5 is a detail showing of a hydraulic-mechanism for actuating alifting jack according to the invention;

Fig. 6 is a detail showing of the mechanism of Fig. 5;

Figs 7 and 8 are vertical and horizontal sectional views, respectively,of further details ofthe mechanism of Fig. 5 ;y and Figs. 9 and l0 arevertical andr horizontal sectional views, respectively, showingyetfurth'rdetails of the mechanism of Fig. 5; o

Referring first to Fig. l, designated by 4 is acylinder in which mayslide a piston 3'. The lower= most end of this piston is recessed as atI9. Mounted in this recess is a metallic collar t bot= tomed with anannular member 2 made ofplastio or other suitable material, the ensembleof I and 2 forming a sealing joint. It is readily understood that themetallic collar I serves to guide the piston 3 in cylinder 4, while theplastic member; insures the tightness between the parts 3 and'j'fl'.

Although the members I and 2 may be mountedY in the recess i9 withoutlbeing made fast thereto,r it is preferable to provide an annular abut-.-ment member 20 to prevent the members I V,s iiicl 2 from coming off thepiston.

Referring to Fig. 2 showing a hydraulic `telescoping jack, designated byI5 is 'the base f this jack, Id is its housing, I?`-I its pump, while,by la is designated a. controlling devicefor actuat ing said pump.Designated by I3 is afrst cylinder of the jack, in which may slide asecond cylinder I'I acting as piston with respect to the cylinder I3..ADesignated by 6 is a second piston slidable in the cylinder II. By 5 isdesignated the usual screw which is intended to contact, for exanjiple,la vehicle, axle priorI to lifting the jack. u V

The lowermost ends of the twopistons 6 and II are recessed as at I9a andI 9b, respectively. On each of these recesses is slid a gasket accordingto the invention, constituted by a metallic collar I and an annularmember 2 made of plastic or elastic material. Designated by I and IIlaare abutment members adapted to maintain the gaskets in place. Thepistons 6 and II are guided by the annular members 'I and I, whileannular elastic members 8 serve as dirt catchers.

It is clear that with the gasket according to the invention the twopistons may move down to the bottom of respective cylinders, in factdown to the bottom of cylinder I3, so that the volume of the jack may bereduced to its minimum. An abutment 28 serves to push the cylinder IIinto cylinder I3.

Referring to Fig. 3, by 3 is designated a piston located in its cylinder4. Formed in the piston and cylinder are grooves 33; a piano wire 34 islocated in the cylinder Vgroove 33 and a piano wire 35 is located in thepiston groove 33. It is clear that when the piston 3 while movingupwards reaches the position shown in Fig. 3, its wire 35 abuts againstthe wire 34 of cylinder 4.

Referring to Fig. 4, there is shown a hydraulic telescoping jackVembodying all the features of the invention. Designated by I5 is thebase of this jack, I4 is its outer casing, while I6-II-I8 is its pump.Screwed into the base I5 is a rst cylinder I3 adapted to receive asecond cylinder II acting as a piston with respect to the cylinder I3,while said second cylinder II is adapted to receive a second piston 6carrying the usual lifting screw 5. The tightness between the saidpistons and the cylinders is insured by gaskets '-25 The upwarddisplacement of the piston is limited by an arrangement similar to thatillustrated in Fig. 3, said arrangement comprising grooves formed in thecylinder and the piston and adapted to receive piano wires 34 Yand35,respectively. 'Ihe telescopic movements of pistons 6 and I I in theirrespective cylinders II and I3 are guided on one hand -by the uppermembers 1 and I and on the other hand .by the lower members 'I and I.Plastic or elastic rings 8 serve as dust and dirt catchers. An abutment28 serves to push the cylinder II into cylinder I3. Y

The member I is on one hand suitably fastened to the cylinder I3 and onthe other hand maintained in place .by a piano wire 38 engaged into agroove formed at the uppermost end of the cylinder I I. Similarly, thegaskets I-2 are maintained in place by piano wires 2I engaged each in agroove formed in the corresponding piston. Although these dierentmembers may be maintained in place in any other way, it is preferred toemploy, as abutments, piano wire engaged into annular grooves, even whenthere is only `one groove receiving only one piano wire.

It is to be noted that all cylindrical parts employed are made withoutany protrusions from their walls, wherefore the fabrication thereof isgreatly facilitated.

VIn Figs. 5 to 10 are illustrated, by way of example, a mechanism andsome parts of it for actuating the hydraulic telescoping jack shown inFig. 4. In Fig. 5, I4 is the casing of the jack, while the movableportion thereof is designated by II, comprising two pistons. Designatedby I8 is the pump adapted to communicate, on the one hand, through apassage 50 with the oil reservoir in the said casing and, on the otherhand, through a passage 5I with the cylinder I3 for thejack, saidcylinder being adapted to communicate through the passage 5I, a releaseconduit 5 I a and a passage 48 in a drainer 49, with the said reservoir.The drainer 49 comprises a valve operating a rod or piston 45 which isurged upwardly by suitable springs and has a head extending through andbeyond the upper wall portion of said reservoir. The passage 5Ia isnormally closed by a ball 41 applied against its seat by a suitablespring. For setting in communication the passages 5I, 5Ia and 48, andconsequently the interior of the cylinders and the casing, it will besucient to press said piston head downwardly in order that the narrowpiston end 48 may remove the ball 41 from its seat. When the draining iscompleted, the pressure on Athe piston head is released and saidcommunication is then automatically interrupted under the action of thespring.

In order that the desired thrust may be exerted against the piston head45, the upper portion of the casing I4 is formed with a housing whoseupper edge is curved so as to form a shoulder 52. The lever 44, which isintended to actuate the pump I8, is normally engaged into the yoke 53pivoted as at 54 on the casing I4. For effecting the draining it issuicient to pull the lever from the left to the right in order that itmayy pass from its position 44a, in which it has been en-` gaged intothe yoke 53, to its position 44 indicated by full lines in Fig. 5. Atthis instant it suffices to press the lever end, held in the hand,down,- wardly in order that it may be brought, while pivoting about thepoint 55, from the position 44 to the position 44D in which this leverpresses against the piston head 45.

In order that the end of lever 44 may be maintained in the housing, sothat the jack may-be withdrawn from under the vehicle after draining,there is provided in the said end a hole 51 (Fig. 6) into which may .beengaged a pin 56 made fast to the shoulder 52. Instead of suchpin-and-hole arrangement, there maybe provided on the casing I4 twoprotrusions 59, 60 (Figs. '7 and 8) between which may be engaged a pin6I carried by the lever, or else there may be pro-l 65 into which may beengaged an unreduced pore tion thereof.

It should be understood that the inventionis` not limited to thespecific details shown, in par-g ticular to the shape of the metallicpart of gasket or to that of its expansible part or to the manner inwhich these parts are interconnected, nor is it limited to theparticular mechanism described and shown for actuating the lifting jackVcon--V templated, as changes could be effected therein withoutsubstantially departing from the spirit of the invention which isintended to be defined .by the claims herein.

y I claim:

1. Ina hydraulic lifting jack of the telescopicv type, the combinationwith a pump, a reservoir for pressure Huid, a fixed cylinder closed atits lower end, passages forming communication between said reservoir andsaid xed cylinder by way of the pump. a release conduit for direct flowof duid between said reservoir and said fixed cylinder, and manuallyoperable means for controlling the ow through'said release conduitl ofan inner end portion of reduced o uter diameter,

functioning to abut against the bottom of said fixed cylinder, anannular member positioned on said inner end portion of the ram cylinderto guide the same in said Xed cylinder and carrying a packing memberhaving a U-shape in crosssection one leg of which forms a seal with thewall of said xed cylinder and the other leg of which form-s a seal withsaid inner end portion of the ram cylinder, a second annular memberpositioned on the inner end portion of said ram to guide the latter insaid ram cylinder and carrying a packing member having a U-shape incross-section one leg of which forms a seal with the wall of said ramcylinder and the other a seal with the inner end portion of said ram,means mounted on the circumferential periphery of said inner endportions to hold said annular members and said packing members inposition, and means to limit the upward movement of said ram cylinderand of said ram.

2. A hydraulic lifting jack according to claim 1, wherein the means tohold said annular members and said packing members in position on saidinner end portions are constituted by removable spring members insertedin annular grooves provided in the circumferential periphery of saidinner end portions.

3. A hydraulic lifting jack according to claim l, wherein the means tolimit the upward movement of said ram and said ram cylinder areconstituted by removable Aco--operating spring members inserted inannular grooves provided, respectively, in the inner wall of said xedcylinder, in the inner and outer walls of Said ram cylinder and in theouter wall of said ram.

4. A hydraulic lifting jack according to claim 1, wherein the manuallyoperable means for controlling the sow through said messe conduitincludes a spring loaded check valve mounted in said release conduit toprevent ilow from the fixed cylinder to the reservoir, a valve operatingrod extending outwardly from the jack body arranged to open said checkvalve against the action of said spring, a removable lever for actuatingeither said pump or said valve operating rod, pivot means associatedwith said pump to actuate the same through said lever, and means on saidjack body forming a fulcrum point for said lever near said valveoperating rod, said fulcrum point permitting to actuate said valveoperating rod through said lever independently of said pump actuatingpivot means.

JEAN LOUIS GRATZMULLER.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS (Addition to No. 601,282)

